libstdc++
condition_variable
1 // <condition_variable> -*- C++ -*-
2 
3 // Copyright (C) 2008, 2009 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10 
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
15 
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19 
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
24 
25 /** @file condition_variable
26  * This is a Standard C++ Library header.
27  */
28 
29 #ifndef _GLIBCXX_CONDITION_VARIABLE
30 #define _GLIBCXX_CONDITION_VARIABLE 1
31 
32 #pragma GCC system_header
33 
34 #ifndef __GXX_EXPERIMENTAL_CXX0X__
35 # include <c++0x_warning.h>
36 #else
37 
38 #include <chrono>
39 #include <mutex> // unique_lock
40 
41 #if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
42 
43 namespace std
44 {
45  /**
46  * @defgroup condition_variables Condition Variables
47  * @ingroup concurrency
48  *
49  * Classes for condition_variable support.
50  * @{
51  */
52 
53  /// condition_variable
54  class condition_variable
55  {
56  typedef chrono::system_clock __clock_t;
57  typedef __gthread_cond_t __native_type;
58  __native_type _M_cond;
59 
60  public:
61  typedef __native_type* native_handle_type;
62 
63  condition_variable();
64  ~condition_variable();
65 
66  condition_variable(const condition_variable&) = delete;
67  condition_variable& operator=(const condition_variable&) = delete;
68 
69  void
70  notify_one();
71 
72  void
73  notify_all();
74 
75  void
76  wait(unique_lock<mutex>& __lock);
77 
78  template<typename _Predicate>
79  void
80  wait(unique_lock<mutex>& __lock, _Predicate __p)
81  {
82  while (!__p())
83  wait(__lock);
84  }
85 
86  template<typename _Duration>
87  bool
88  wait_until(unique_lock<mutex>& __lock,
89  const chrono::time_point<__clock_t, _Duration>& __atime)
90  { return __wait_until_impl(__lock, __atime); }
91 
92  template<typename _Clock, typename _Duration>
93  bool
94  wait_until(unique_lock<mutex>& __lock,
95  const chrono::time_point<_Clock, _Duration>& __atime)
96  {
97  // DR 887 - Sync unknown clock to known clock.
98  typename _Clock::time_point __c_entry = _Clock::now();
99  __clock_t::time_point __s_entry = __clock_t::now();
100  chrono::nanoseconds __delta = __atime - __c_entry;
101  __clock_t::time_point __s_atime = __s_entry + __delta;
102 
103  return __wait_until_impl(__lock, __s_atime);
104  }
105 
106  template<typename _Clock, typename _Duration, typename _Predicate>
107  bool
108  wait_until(unique_lock<mutex>& __lock,
109  const chrono::time_point<_Clock, _Duration>& __atime,
110  _Predicate __p)
111  {
112  while (!__p())
113  if (!wait_until(__lock, __atime))
114  return __p();
115 
116  return true;
117  }
118 
119  template<typename _Rep, typename _Period>
120  bool
121  wait_for(unique_lock<mutex>& __lock,
122  const chrono::duration<_Rep, _Period>& __rtime)
123  { return wait_until(__lock, __clock_t::now() + __rtime); }
124 
125  template<typename _Rep, typename _Period, typename _Predicate>
126  bool
127  wait_for(unique_lock<mutex>& __lock,
128  const chrono::duration<_Rep, _Period>& __rtime,
129  _Predicate __p)
130  { return wait_until(__lock, __clock_t::now() + __rtime, std::move(__p)); }
131 
132  native_handle_type
133  native_handle()
134  { return &_M_cond; }
135 
136  private:
137  template<typename _Clock, typename _Duration>
138  bool
139  __wait_until_impl(unique_lock<mutex>& __lock,
140  const chrono::time_point<_Clock, _Duration>& __atime)
141  {
142  chrono::time_point<__clock_t, chrono::seconds> __s =
143  chrono::time_point_cast<chrono::seconds>(__atime);
144 
145  chrono::nanoseconds __ns =
146  chrono::duration_cast<chrono::nanoseconds>(__atime - __s);
147 
148  __gthread_time_t __ts =
149  {
150  static_cast<std::time_t>(__s.time_since_epoch().count()),
151  static_cast<long>(__ns.count())
152  };
153 
154  __gthread_cond_timedwait(&_M_cond, __lock.mutex()->native_handle(),
155  &__ts);
156 
157  return _Clock::now() < __atime;
158  }
159  };
160 
161  /// condition_variable_any
162  // Like above, only mutex may not have try_lock.
163  class condition_variable_any
164  {
165  typedef __gthread_cond_t __native_type;
166  __native_type _M_cond;
167 
168  public:
169  typedef __native_type* native_handle_type;
170 
171  condition_variable_any();
172  ~condition_variable_any();
173 
174  condition_variable_any(const condition_variable_any&) = delete;
175  condition_variable_any& operator=(const condition_variable_any&) = delete;
176 
177  void
178  notify_one();
179 
180  void
181  notify_all();
182 
183  template<typename _Lock>
184  void
185  wait(_Lock& __lock);
186 
187  template<typename _Lock, typename _Predicate>
188  void
189  wait(_Lock& __lock, _Predicate __p);
190 
191  template<typename _Lock, typename _Clock, typename _Duration>
192  bool
193  wait_until(_Lock& __lock,
194  const chrono::time_point<_Clock, _Duration>& __atime);
195 
196  template<typename _Lock, typename _Clock,
197  typename _Duration, typename _Predicate>
198  bool
199  wait_until(_Lock& __lock,
200  const chrono::time_point<_Clock, _Duration>& __atime,
201  _Predicate __p);
202 
203  template<typename _Lock, typename _Rep, typename _Period>
204  bool
205  wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __rtime);
206 
207  template<typename _Lock, typename _Rep,
208  typename _Period, typename _Predicate>
209  bool
210  wait_for(_Lock& __lock,
211  const chrono::duration<_Rep, _Period>& __rtime, _Predicate __p);
212 
213  native_handle_type
214  native_handle()
215  { return &_M_cond; }
216  };
217 
218  // @} group condition_variables
219 }
220 
221 #endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1
222 
223 #endif // __GXX_EXPERIMENTAL_CXX0X__
224 
225 #endif // _GLIBCXX_CONDITION_VARIABLE